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Saturday, June 07, 2008


From a discussion on Jerry Pournelle's Chaos Manor:

Regarding the availability of nuclear fuel - My understanding is that Professor Bernard Cohen calculated some years ago that it would be possible to obtain enough uranium from sea water to keep our current nuclear industry going till the Sun explodes. This would also require breeder reactors & recovering uranium from "waste" but we know how to do all that. Admittedly that much uranium isn't in the sea at the moment. He is fiddling a bit by assuming that the rivers will keep running the stuff down to the sea.

Boiling the seas would cost rather more than current mining but fuel is a far smaller component of nuclear power than of the conventional stuff so it doesn't much matter.

Even Wikipedia is forced to acknowledge that there are enormous resources though naturally it has been edited into an addendum at the end of their article

And when the uranium runs out we can use thorium.

Neil Craig

The important point is that there is enough uranium economically available to keep us going until we have solar power satellites and fusion plants. See A Step Farther Out; I dealt with much of this in my book. My Survival With Style presentation used to be fairly popular -- at least I got fairly high speaking fees for it -- and went into details about energy and other resources. It's in A Step Farther

UPDATE - Jerry has published this response, which confirms & extends what I said:
Dear Dr. Pournelle,

Best wishes for a speedy recovery!

I used to spend a lot of time arguing the nuclear power issue on local dial-up bulletin board systems and Usenet, including lots of time (pre-Internet) in various libraries looking up facts and figures.

My understanding of the figures on how long our proven reserves of uranium would last is that the quoted numbers are assuming that our current once-through fuel cycle is left in place permanently, and we'll continue throwing away the plutonium bred in the reactor and the leftover U235 along with the un-transmuted U238 until the end.

Buildup of neutron-absorbing fission products, not burn-up of all the fissionable isotopes, is the major factor in when a fuel rod must be replaced.

Just separating out the plutonium isotopes and the unburned uranium and recycling them into new fuel multiplies the length of time those proven reserves will last by several times, even without going to breeder reactors. Jimmy Carter banned fuel reprocessing in the U.S. by executive decree. One of my greatest disappointments with all the presidents after Carter is that none of them ever saw fit to get around to un-decreeing the ban.

Breeder reactors multiply how long our proven reserves will last by something like an order of magnitude. Then there's thorium breeders. According to my CRC handbook, thorium is "about as common as lead", and "there is probably more available energy in the earth's crust from thorium than from uranium and all fossil fuels put together."

And finally, according to a bit in Petr Beckmann's excellent book "The Health Hazards of Not Going Nuclear", written back around 1974 or so, the Japanese at that time had an ion-exchange process that could extract uranium from sea water at a cost of about $200/pound in 1974 dollars. That's probably about as inexhaustible as inexhaustible gets.

In my judgment there is no danger of a shortage of nuclear fuels.

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